Re: [PATCH v3 3/3] genirq: reimplement exit_irq_thread() hook via task_work_queue()

[Thomas Gleixner <tglx@linutronix.de>]

On Thu, 12 Apr 2012, Oleg Nesterov wrote:

> exit_irq_thread() and task->irq_thread are needed to handle
> the unexpected (and unlikely) exit of irq-thread.
> 
> We can use task_work instead and make this all private to
> kernel/irq/manage.c, simplification plus micro-optimization.
> 
> 1. rename exit_irq_thread() to irq_thread_dtor(), make it
>    static, and move it up before irq_thread().
> 
> 2. change irq_thread() to do task_queue_work(irq_thread_dtor)
>    at the start and task_work_cancel() before return.
> 
>    tracehook_notify_resume() can never play with kthreads,
>    only do_exit()->exit_task_work() can call the callback
>    and this is what we want.
> 
> 3. remove task_struct->irq_thread and the special hook
>    in do_exit().
> 
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
> ---
>  include/linux/interrupt.h |    4 --
>  include/linux/sched.h     |   10 +-----
>  kernel/exit.c             |    2 -
>  kernel/irq/manage.c       |   69 +++++++++++++++++++++-----------------------
>  4 files changed, 35 insertions(+), 50 deletions(-)

Nice cleanup.

Reviewed-by: Thomas Gleixner <tglx@linutronix.de>